The present invention generally pertains to the field of communication devices and methods for determining position. More particularly, the present invention is related to communication of position.
Position Determination System (PDS) devices such as devices that determine position using the satellites of the US Global Positioning System typically include a GPS antenna, a GPS receiver, a GPS processor, and a data storage device. Signals from the GPS are received by the GPS antenna, processed by the GPS receiver and position is determined by the GPS processor. However, typically, the computation of position using signals from the GPS system gives position in an Earth Centered Earth Fixed (ECEF) format that includes ECEF coordinates.
The indication of position in ECEF coordinates is not particularly useful for most applications. Maritime users, campers, hikers, and other users in remote locations typically want to know their position in terms of latitude and longitude. Users in urban areas typically want to know their position as a street address. Alternatively, users desire to know position relative to major landmarks, or relative to nearby cross streets.
The conversion of position into other coordinate systems requires that conversion algorithms and/or extensive databases be stored in the PDS device. This requires a high capacity memory storage device. High capacity memory storage devices sufficient to store the large databases and conversion algorithms are quite expensive. Also, usage is complicated by the fact that new streets, addresses, and landmarks are constantly being added and existing streets, addresses and landmarks are frequently changed. Therefore, the databases used must be frequently updated. The updating process is expensive and time consuming. In addition, the microprocessor must be quick and powerful to search the database and convert the determined position into the desired reference system in a timely manner. This adds even more expense to the PDS device.
As usage of the GPS has grown in popularity, there has been a need for economical devices that allow for the determination of the position of the user. However, GPS processors are expensive as are memory storage devices. In addition, maintenance of devices for determining position that indicated position in different formats is expensive and difficult due to the need to frequently update the stored databases.
Recently, message transmission devices that allow persons to easily send messages have become popular. These message transmission devices include computers, handheld computers, digital telephones and digital pagers. The communication systems that are used by recent message transmission devices include, for example, the internet, cellular telephone networks, paging networks, wireless data transmission networks, telephone transmission lines and cable systems.
Typically, message transmission devices include a keypad that allows a user to compose a message. Many message transmission devices use commonly available software programs such as Eudora, Netscape Navigator, etc. that generate messages conforming to a standard format. A typical message contains a body and one or more headers. The headers indicate the final destination to which the message is to be sent and the identity of the sender.
One commonly used format for messages is the Standard Mail Transmission Protocol (SMTP) format. The SMTP format is used for almost all internet message transmissions. Due to the popularity and widespread use of the SMTP format for internet transmission, the SMTP format is also being increasingly used for non-internet communications.
Servers are used to route messages to their final destination. Servers that route messages that conform to the SMTP format (SMTP servers) route messages based on information contained in a header. Typically, such servers only route messages, they do not alter the text in the body of the message. Instead, headers are often added, deleted, or otherwise altered by the server to route the message to the desired final destination.
Because of the relatively high cost of adding position determination capabilities to message transmission devices, these devices do not typically include position determination capabilities. However, it is often desirable for a user of a message transmission device to know his position. In addition, the user""s position is often needed to properly route a message. This is particularly true when a user of a message transmission device needs to contact or locate the nearest facility of a service provider such as, for example, the nearest gas station, the nearest bank branch, etc.
What is needed is a way for a user of a message transmission device to determine position and to indicate position in a message. In addition, a way to determine position is needed that couples position to a user in a desired format, without the need to store and update extensive databases on the device being used. Still another need exists for a device that meets the above-listed needs and that is inexpensive. Yet another need exists for a method and apparatus for routing of messages according to the position of the sender. The present invention provides a solution to the above needs.
The method and apparatus of the present invention allows for inexpensively indicating position in a message. In addition, the method and apparatus of the present invention provides for an apparatus that can be used to determine position that is inexpensive to manufacture. Also, the method and apparatus allows for the indication of position in a desired format, without the need to store and update extensive databases on the device being used to generate the message. Also, the method and apparatus of the present invention allows for routing of messages based on the position of the sender.
A message transmission device is described that is adapted to send and receive messages. In one embodiment, the message transmission device includes a message transmission unit that is coupled to a position determination system. The message transmission unit can employ any of a number of known methods for sending and receiving messages, and can include, for example, a radio modem, a pager, a telephone modem, etc. In one embodiment, the message transmission unit is a digital pager that includes alphanumeric input keys for data input. Alternatively, the message transmission unit includes a computer that is coupled to a radio modem that is adapted to communicate through a cellular communication system.
A server is described that is adapted to send and receive messages. The server is adapted to receive messages from the message transmission device and perform instructions that relate to position indicated in received messages. In one embodiment, the server is coupled to the internet and is adapted to receive messages formatted in Standard Mail Transmission Protocol (SMTP) format. In such an embodiment, messages are coupled over a communication system such as a cellular communication system, paging network, etc. to the server. The server then generates and sends a message that complies with the indicated instruction.
In one embodiment, instructions indicate routing. Examples of indications of routing include return routing, automated routing, and routing to addressee. When return routing is indicated, a message that complies with the indicated instruction is routed back to the message transmission device. Automated routing allows for routing that is dependent on the position of the message transmission device.
In one embodiment, instructions also indicate the format in which the position information is to be indicated. That is, the position information is indicated in the indicated formats. Formats include, for example, Earth Centered Earth Fixed (ECEF) coordinates, World Geodetic Survey 84 (WGS 84) coordinates, map coordinates, Latitude and Longitude coordinates, street address, street and nearest cross street, etc.
By indicating return routing in the instruction, a user can obtain location in any of a number of desired formats without the need to store extensive databases in the message transmission unit. Instead, databases necessary for conversion of position into the various formats are centrally located on the server. Because a single server can service many message transmission units, database maintenance and updating is facilitated. The message transmission device of the present invention is less expensive than prior art devices that are capable of determining position in a particular format because each message transmission device does not have to include databases and conversion programs for converting position into a desired format as are required by prior art devices.
In one embodiment of the present invention, a message transmission device is disclosed that does not include a PDS processing capabilities. In this embodiment, the message transmission device includes a PDS antenna and PDS receiver, but does not include a PDS processor. Instead of processing PDS data at the message transmission device, in this embodiment, PDS data is processed at the server. More particularly, in one embodiment, PDS data is received at the message transmission device and is transmitted to the server, along with an indication of the time that the PDS data is received. The server then determines the position of the message transmission device and sends a return message to the message transmission device that indicates the position of the message transmission device. This allows for the determination of position using a message transmission device that is less expensive than prior art devices for determining position. More particularly, significant cost savings are realized by eliminating the PDS processor. Also, extensive databases for converting position into a desired format are not required as are required by prior art systems for determining position in a given format.
The present method and apparatus allows a user of a message transmission device to determine position and to indicate position in a message. In addition, the method and apparatus of the present invention provides a way to determine position in a desired format, without the need to store and update extensive databases on the device being used. In addition, the present invention meets the above-listed needs and is inexpensive as well. Moreover, the apparatus and method of the present invention allows for routing of messages according to the position of the sender.